blob: 26c51e8e9c5f94959c976e14588e79e5e7b290cd [file] [log] [blame]
/* GStreamer
* Copyright (C) <2016> Matthew Waters <matthew@centricular.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
/*
* This file was modified from videobalance and converted to OpenGL
*/
/**
* SECTION:element-glcolorbalance
* @title: glcolorbalance
*
* Adjusts brightness, contrast, hue, saturation on a video stream.
*
* ## Example launch line
* |[
* gst-launch-1.0 videotestsrc ! glupload ! glcolorbalance saturation=0.0 ! glcolorconvert ! gldownload ! ximagesink
* ]| This pipeline converts the image to black and white by setting the
* saturation to 0.0.
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <string.h>
#include <gst/gl/gstglfuncs.h>
#include <gst/math-compat.h>
#include <gst/video/colorbalance.h>
#include "gstglcolorbalance.h"
GST_DEBUG_CATEGORY_STATIC (glcolorbalance_debug);
#define GST_CAT_DEFAULT glcolorbalance_debug
/* GstGLColorBalance properties */
#define DEFAULT_PROP_CONTRAST 1.0
#define DEFAULT_PROP_BRIGHTNESS 0.0
#define DEFAULT_PROP_HUE 0.0
#define DEFAULT_PROP_SATURATION 1.0
#define GST_GL_COLOR_BALANCE_VIDEO_CAPS \
"video/x-raw(" GST_CAPS_FEATURE_MEMORY_GL_MEMORY "), " \
"format = (string) RGBA, " \
"width = " GST_VIDEO_SIZE_RANGE ", " \
"height = " GST_VIDEO_SIZE_RANGE ", " \
"framerate = " GST_VIDEO_FPS_RANGE ", " \
"texture-target = (string) { 2D, external-oes } " \
" ; " \
"video/x-raw(" GST_CAPS_FEATURE_MEMORY_GL_MEMORY "," \
GST_CAPS_FEATURE_META_GST_VIDEO_OVERLAY_COMPOSITION "), " \
"format = (string) RGBA, " \
"width = " GST_VIDEO_SIZE_RANGE ", " \
"height = " GST_VIDEO_SIZE_RANGE ", " \
"framerate = " GST_VIDEO_FPS_RANGE ", " \
"texture-target = (string) { 2D, external-oes }"
static GstStaticPadTemplate gst_gl_color_balance_element_src_pad_template =
GST_STATIC_PAD_TEMPLATE ("src",
GST_PAD_SRC,
GST_PAD_ALWAYS,
GST_STATIC_CAPS (GST_GL_COLOR_BALANCE_VIDEO_CAPS));
static GstStaticPadTemplate gst_gl_color_balance_element_sink_pad_template =
GST_STATIC_PAD_TEMPLATE ("sink",
GST_PAD_SINK,
GST_PAD_ALWAYS,
GST_STATIC_CAPS (GST_GL_COLOR_BALANCE_VIDEO_CAPS));
/* *INDENT-OFF* */
static const gchar color_balance_frag_OES_preamble[] =
"#extension GL_OES_EGL_image_external : require\n"
"#ifdef GL_ES\n"
"precision mediump float;\n"
"#endif\n"
"uniform samplerExternalOES tex;\n";
static const gchar color_balance_frag_2D_preamble[] =
"#ifdef GL_ES\n"
"precision mediump float;\n"
"#endif\n"
"uniform sampler2D tex;\n";
static const gchar color_balance_frag_templ[] =
"%s\n" // Preamble
"uniform float brightness;\n"
"uniform float contrast;\n"
"uniform float saturation;\n"
"uniform float hue;\n"
"varying vec2 v_texcoord;\n"
"#define from_yuv_bt601_offset vec3(-0.0625, -0.5, -0.5)\n"
"#define from_yuv_bt601_rcoeff vec3(1.164, 0.000, 1.596)\n"
"#define from_yuv_bt601_gcoeff vec3(1.164,-0.391,-0.813)\n"
"#define from_yuv_bt601_bcoeff vec3(1.164, 2.018, 0.000)\n"
"#define from_rgb_bt601_offset vec3(0.0625, 0.5, 0.5)\n"
"#define from_rgb_bt601_ycoeff vec3(0.256816, 0.504154, 0.0979137)\n"
"#define from_rgb_bt601_ucoeff vec3(-0.148246, -0.29102, 0.439266)\n"
"#define from_rgb_bt601_vcoeff vec3(0.439271, -0.367833, -0.071438)\n"
"#define PI 3.14159265\n"
"\n"
"vec3 yuv_to_rgb (vec3 val) {\n"
" vec3 rgb;\n"
" val += from_yuv_bt601_offset;\n"
" rgb.r = dot(val, from_yuv_bt601_rcoeff);\n"
" rgb.g = dot(val, from_yuv_bt601_gcoeff);\n"
" rgb.b = dot(val, from_yuv_bt601_bcoeff);\n"
" return rgb;\n"
"}\n"
"vec3 rgb_to_yuv (vec3 val) {\n"
" vec3 yuv;\n"
" yuv.r = dot(val.rgb, from_rgb_bt601_ycoeff);\n"
" yuv.g = dot(val.rgb, from_rgb_bt601_ucoeff);\n"
" yuv.b = dot(val.rgb, from_rgb_bt601_vcoeff);\n"
" yuv += from_rgb_bt601_offset;\n"
" return yuv;\n"
"}\n"
/* 224 = 256 - (256 - 240) - 16*/
"float luma_to_narrow (float luma) {\n"
" return (luma + 16.0 / 256.0) * 219.0 / 256.0;"
"}\n"
"float luma_to_full (float luma) {\n"
" return (luma * 256.0 / 219.0) - 16.0 / 256.0;"
"}\n"
"void main () {\n"
" vec3 yuv;\n"
/* operations translated from videobalanceand tested with glvideomixer
* with one pad's paremeters blend-equation-rgb={subtract,reverse-subtract},
* blend-function-src-rgb=src-color and blend-function-dst-rgb=dst-color */
" float hue_cos = cos (PI * hue);\n"
" float hue_sin = sin (PI * hue);\n"
" vec4 rgba = %s (tex, v_texcoord);\n" /* texture2D / texture2DOES */
" yuv = rgb_to_yuv (rgba.rgb);\n"
" yuv.x = clamp (luma_to_narrow (luma_to_full(yuv.x) * contrast) + brightness, 0.0, 1.0);\n"
" vec2 uv = yuv.yz;\n"
" yuv.y = clamp (0.5 + (((uv.x - 0.5) * hue_cos + (uv.y - 0.5) * hue_sin) * saturation), 0.0, 1.0);\n"
" yuv.z = clamp (0.5 + (((0.5 - uv.x) * hue_sin + (uv.y - 0.5) * hue_cos) * saturation), 0.0, 1.0);\n"
" rgba.rgb = yuv_to_rgb (yuv);\n"
" gl_FragColor = rgba;\n"
"}\n";
/* *INDENT-ON* */
enum
{
PROP_0,
PROP_CONTRAST,
PROP_BRIGHTNESS,
PROP_HUE,
PROP_SATURATION
};
static void gst_gl_color_balance_colorbalance_init (GstColorBalanceInterface *
iface);
static void gst_gl_color_balance_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec);
static void gst_gl_color_balance_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec);
#define gst_gl_color_balance_parent_class parent_class
G_DEFINE_TYPE_WITH_CODE (GstGLColorBalance, gst_gl_color_balance,
GST_TYPE_GL_FILTER,
G_IMPLEMENT_INTERFACE (GST_TYPE_COLOR_BALANCE,
gst_gl_color_balance_colorbalance_init));
static GstCaps *
gcb_transform_internal_caps (GstGLFilter * filter,
GstPadDirection direction, GstCaps * caps, GstCaps * filter_caps)
{
GstCaps *tmp = gst_caps_make_writable (caps);
gint i;
/* If we're not in passthrough mode, we can only output 2D textures,
* but can always receive any compatible texture.
* This function is not called in passthrough mode, so we can do the
* transform unconditionally */
for (i = 0; i < gst_caps_get_size (tmp); i++) {
GstStructure *outs = gst_caps_get_structure (tmp, i);
if (direction == GST_PAD_SINK) {
gst_structure_set (outs, "texture-target", G_TYPE_STRING,
gst_gl_texture_target_to_string (GST_GL_TEXTURE_TARGET_2D), NULL);
} else {
gst_structure_remove_field (outs, "texture-target");
}
}
return tmp;
}
static gboolean
gst_gl_color_balance_is_passthrough (GstGLColorBalance * glcolorbalance)
{
return glcolorbalance->contrast == 1.0 &&
glcolorbalance->brightness == 0.0 &&
glcolorbalance->hue == 0.0 && glcolorbalance->saturation == 1.0;
}
static void
gst_gl_color_balance_update_properties (GstGLColorBalance * glcolorbalance)
{
gboolean current_passthrough, passthrough;
GstBaseTransform *base = GST_BASE_TRANSFORM (glcolorbalance);
GST_OBJECT_LOCK (glcolorbalance);
passthrough = gst_gl_color_balance_is_passthrough (glcolorbalance);
GST_OBJECT_UNLOCK (glcolorbalance);
current_passthrough = gst_base_transform_is_passthrough (base);
gst_base_transform_set_passthrough (base, passthrough);
if (current_passthrough != passthrough)
gst_base_transform_reconfigure_src (base);
}
static gboolean
_create_shader (GstGLColorBalance * balance)
{
GstGLBaseFilter *base_filter = GST_GL_BASE_FILTER (balance);
GstGLFilter *filter = GST_GL_FILTER (balance);
GError *error = NULL;
gchar *frag_str;
if (balance->shader)
gst_object_unref (balance->shader);
/* Can support rectangle textures in the future if needed */
if (filter->in_texture_target == GST_GL_TEXTURE_TARGET_2D)
frag_str =
g_strdup_printf (color_balance_frag_templ,
color_balance_frag_2D_preamble, "texture2D");
else
frag_str =
g_strdup_printf (color_balance_frag_templ,
color_balance_frag_OES_preamble, "texture2D");
if (!(balance->shader =
gst_gl_shader_new_link_with_stages (base_filter->context, &error,
gst_glsl_stage_new_default_vertex (base_filter->context),
gst_glsl_stage_new_with_string (base_filter->context,
GL_FRAGMENT_SHADER, GST_GLSL_VERSION_NONE,
GST_GLSL_PROFILE_ES | GST_GLSL_PROFILE_COMPATIBILITY,
frag_str), NULL))) {
g_free (frag_str);
GST_ELEMENT_ERROR (balance, RESOURCE, NOT_FOUND, ("%s",
"Failed to initialize colorbalance shader"), ("%s",
error ? error->message : "Unknown error"));
return FALSE;
}
g_free (frag_str);
filter->draw_attr_position_loc =
gst_gl_shader_get_attribute_location (balance->shader, "a_position");
filter->draw_attr_texture_loc =
gst_gl_shader_get_attribute_location (balance->shader, "a_texcoord");
return TRUE;
}
static gboolean
gst_gl_color_balance_gl_start (GstGLBaseFilter * base_filter)
{
GstGLColorBalance *balance = GST_GL_COLOR_BALANCE (base_filter);
if (!_create_shader (balance))
return FALSE;
return GST_GL_BASE_FILTER_CLASS (parent_class)->gl_start (base_filter);
}
static void
gst_gl_color_balance_gl_stop (GstGLBaseFilter * base_filter)
{
GstGLColorBalance *balance = GST_GL_COLOR_BALANCE (base_filter);
if (balance->shader)
gst_object_unref (balance->shader);
balance->shader = NULL;
GST_GL_BASE_FILTER_CLASS (parent_class)->gl_stop (base_filter);
}
static void
gst_gl_color_balance_before_transform (GstBaseTransform * base, GstBuffer * buf)
{
GstGLColorBalance *balance = GST_GL_COLOR_BALANCE (base);
GstClockTime timestamp, stream_time;
timestamp = GST_BUFFER_TIMESTAMP (buf);
stream_time =
gst_segment_to_stream_time (&base->segment, GST_FORMAT_TIME, timestamp);
GST_DEBUG_OBJECT (balance, "sync to %" GST_TIME_FORMAT,
GST_TIME_ARGS (timestamp));
if (GST_CLOCK_TIME_IS_VALID (stream_time))
gst_object_sync_values (GST_OBJECT (balance), stream_time);
}
static gboolean
gst_gl_color_balance_filter_texture (GstGLFilter * filter, GstGLMemory * in_tex,
GstGLMemory * out_tex)
{
GstGLColorBalance *balance = GST_GL_COLOR_BALANCE (filter);
if (!balance->shader)
_create_shader (balance);
gst_gl_shader_use (balance->shader);
GST_OBJECT_LOCK (balance);
gst_gl_shader_set_uniform_1f (balance->shader, "brightness",
balance->brightness);
gst_gl_shader_set_uniform_1f (balance->shader, "contrast", balance->contrast);
gst_gl_shader_set_uniform_1f (balance->shader, "saturation",
balance->saturation);
gst_gl_shader_set_uniform_1f (balance->shader, "hue", balance->hue);
GST_OBJECT_UNLOCK (balance);
gst_gl_filter_render_to_target_with_shader (filter, in_tex, out_tex,
balance->shader);
return TRUE;
}
static void
gst_gl_color_balance_finalize (GObject * object)
{
GstGLColorBalance *balance = GST_GL_COLOR_BALANCE (object);
GList *channels = NULL;
channels = balance->channels;
while (channels) {
GstColorBalanceChannel *channel = channels->data;
g_object_unref (channel);
channels->data = NULL;
channels = g_list_next (channels);
}
if (balance->channels)
g_list_free (balance->channels);
G_OBJECT_CLASS (parent_class)->finalize (object);
}
static void
gst_gl_color_balance_class_init (GstGLColorBalanceClass * klass)
{
GObjectClass *gobject_class = (GObjectClass *) klass;
GstElementClass *gstelement_class = (GstElementClass *) klass;
GstBaseTransformClass *trans_class = (GstBaseTransformClass *) klass;
GstGLBaseFilterClass *base_filter_class = (GstGLBaseFilterClass *) klass;
GstGLFilterClass *filter_class = (GstGLFilterClass *) klass;
GST_DEBUG_CATEGORY_INIT (glcolorbalance_debug, "glcolorbalance", 0,
"glcolorbalance");
gst_element_class_add_static_pad_template (gstelement_class,
&gst_gl_color_balance_element_src_pad_template);
gst_element_class_add_static_pad_template (gstelement_class,
&gst_gl_color_balance_element_sink_pad_template);
gobject_class->finalize = gst_gl_color_balance_finalize;
gobject_class->set_property = gst_gl_color_balance_set_property;
gobject_class->get_property = gst_gl_color_balance_get_property;
g_object_class_install_property (gobject_class, PROP_CONTRAST,
g_param_spec_double ("contrast", "Contrast", "contrast",
0.0, 2.0, DEFAULT_PROP_CONTRAST,
GST_PARAM_CONTROLLABLE | G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class, PROP_BRIGHTNESS,
g_param_spec_double ("brightness", "Brightness", "brightness", -1.0, 1.0,
DEFAULT_PROP_BRIGHTNESS,
GST_PARAM_CONTROLLABLE | G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class, PROP_HUE,
g_param_spec_double ("hue", "Hue", "hue", -1.0, 1.0, DEFAULT_PROP_HUE,
GST_PARAM_CONTROLLABLE | G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class, PROP_SATURATION,
g_param_spec_double ("saturation", "Saturation", "saturation", 0.0, 2.0,
DEFAULT_PROP_SATURATION,
GST_PARAM_CONTROLLABLE | G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
gst_element_class_set_static_metadata (gstelement_class, "Video balance",
"Filter/Effect/Video",
"Adjusts brightness, contrast, hue, saturation on a video stream",
"Matthew Waters <matthew@centricular.com>");
trans_class->before_transform =
GST_DEBUG_FUNCPTR (gst_gl_color_balance_before_transform);
trans_class->transform_ip_on_passthrough = FALSE;
base_filter_class->gl_start =
GST_DEBUG_FUNCPTR (gst_gl_color_balance_gl_start);
base_filter_class->gl_stop = GST_DEBUG_FUNCPTR (gst_gl_color_balance_gl_stop);
filter_class->filter_texture =
GST_DEBUG_FUNCPTR (gst_gl_color_balance_filter_texture);
filter_class->transform_internal_caps = gcb_transform_internal_caps;
}
static void
gst_gl_color_balance_init (GstGLColorBalance * glcolorbalance)
{
const gchar *channels[4] = { "HUE", "SATURATION",
"BRIGHTNESS", "CONTRAST"
};
gint i;
/* Initialize propertiews */
glcolorbalance->contrast = DEFAULT_PROP_CONTRAST;
glcolorbalance->brightness = DEFAULT_PROP_BRIGHTNESS;
glcolorbalance->hue = DEFAULT_PROP_HUE;
glcolorbalance->saturation = DEFAULT_PROP_SATURATION;
gst_gl_color_balance_update_properties (glcolorbalance);
/* Generate the channels list */
for (i = 0; i < G_N_ELEMENTS (channels); i++) {
GstColorBalanceChannel *channel;
channel = g_object_new (GST_TYPE_COLOR_BALANCE_CHANNEL, NULL);
channel->label = g_strdup (channels[i]);
channel->min_value = -1000;
channel->max_value = 1000;
glcolorbalance->channels =
g_list_append (glcolorbalance->channels, channel);
}
}
static const GList *
gst_gl_color_balance_colorbalance_list_channels (GstColorBalance * balance)
{
GstGLColorBalance *glcolorbalance = GST_GL_COLOR_BALANCE (balance);
g_return_val_if_fail (glcolorbalance != NULL, NULL);
g_return_val_if_fail (GST_IS_GL_COLOR_BALANCE (glcolorbalance), NULL);
return glcolorbalance->channels;
}
static void
gst_gl_color_balance_colorbalance_set_value (GstColorBalance * balance,
GstColorBalanceChannel * channel, gint value)
{
GstGLColorBalance *vb = GST_GL_COLOR_BALANCE (balance);
gdouble new_val;
gboolean changed = FALSE;
g_return_if_fail (vb != NULL);
g_return_if_fail (GST_IS_GL_COLOR_BALANCE (vb));
g_return_if_fail (channel->label != NULL);
GST_OBJECT_LOCK (vb);
if (!g_ascii_strcasecmp (channel->label, "HUE")) {
new_val = (value + 1000.0) * 2.0 / 2000.0 - 1.0;
changed = new_val != vb->hue;
vb->hue = new_val;
} else if (!g_ascii_strcasecmp (channel->label, "SATURATION")) {
new_val = (value + 1000.0) * 2.0 / 2000.0;
changed = new_val != vb->saturation;
vb->saturation = new_val;
} else if (!g_ascii_strcasecmp (channel->label, "BRIGHTNESS")) {
new_val = (value + 1000.0) * 2.0 / 2000.0 - 1.0;
changed = new_val != vb->brightness;
vb->brightness = new_val;
} else if (!g_ascii_strcasecmp (channel->label, "CONTRAST")) {
new_val = (value + 1000.0) * 2.0 / 2000.0;
changed = new_val != vb->contrast;
vb->contrast = new_val;
}
GST_OBJECT_UNLOCK (vb);
if (changed)
gst_gl_color_balance_update_properties (vb);
if (changed) {
gst_color_balance_value_changed (balance, channel,
gst_color_balance_get_value (balance, channel));
}
}
static gint
gst_gl_color_balance_colorbalance_get_value (GstColorBalance * balance,
GstColorBalanceChannel * channel)
{
GstGLColorBalance *vb = GST_GL_COLOR_BALANCE (balance);
gint value = 0;
g_return_val_if_fail (vb != NULL, 0);
g_return_val_if_fail (GST_IS_GL_COLOR_BALANCE (vb), 0);
g_return_val_if_fail (channel->label != NULL, 0);
if (!g_ascii_strcasecmp (channel->label, "HUE")) {
value = (vb->hue + 1) * 2000.0 / 2.0 - 1000.0;
} else if (!g_ascii_strcasecmp (channel->label, "SATURATION")) {
value = vb->saturation * 2000.0 / 2.0 - 1000.0;
} else if (!g_ascii_strcasecmp (channel->label, "BRIGHTNESS")) {
value = (vb->brightness + 1) * 2000.0 / 2.0 - 1000.0;
} else if (!g_ascii_strcasecmp (channel->label, "CONTRAST")) {
value = vb->contrast * 2000.0 / 2.0 - 1000.0;
}
return value;
}
static GstColorBalanceType
gst_gl_color_balance_colorbalance_get_balance_type (GstColorBalance * balance)
{
return GST_COLOR_BALANCE_HARDWARE;
}
static void
gst_gl_color_balance_colorbalance_init (GstColorBalanceInterface * iface)
{
iface->list_channels = gst_gl_color_balance_colorbalance_list_channels;
iface->set_value = gst_gl_color_balance_colorbalance_set_value;
iface->get_value = gst_gl_color_balance_colorbalance_get_value;
iface->get_balance_type = gst_gl_color_balance_colorbalance_get_balance_type;
}
static GstColorBalanceChannel *
gst_gl_color_balance_find_channel (GstGLColorBalance * balance,
const gchar * label)
{
GList *l;
for (l = balance->channels; l; l = l->next) {
GstColorBalanceChannel *channel = l->data;
if (g_ascii_strcasecmp (channel->label, label) == 0)
return channel;
}
return NULL;
}
static void
gst_gl_color_balance_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec)
{
GstGLColorBalance *balance = GST_GL_COLOR_BALANCE (object);
gdouble d;
const gchar *label = NULL;
GST_OBJECT_LOCK (balance);
switch (prop_id) {
case PROP_CONTRAST:
d = g_value_get_double (value);
GST_DEBUG_OBJECT (balance, "Changing contrast from %lf to %lf",
balance->contrast, d);
if (d != balance->contrast)
label = "CONTRAST";
balance->contrast = d;
break;
case PROP_BRIGHTNESS:
d = g_value_get_double (value);
GST_DEBUG_OBJECT (balance, "Changing brightness from %lf to %lf",
balance->brightness, d);
if (d != balance->brightness)
label = "BRIGHTNESS";
balance->brightness = d;
break;
case PROP_HUE:
d = g_value_get_double (value);
GST_DEBUG_OBJECT (balance, "Changing hue from %lf to %lf", balance->hue,
d);
if (d != balance->hue)
label = "HUE";
balance->hue = d;
break;
case PROP_SATURATION:
d = g_value_get_double (value);
GST_DEBUG_OBJECT (balance, "Changing saturation from %lf to %lf",
balance->saturation, d);
if (d != balance->saturation)
label = "SATURATION";
balance->saturation = d;
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
GST_OBJECT_UNLOCK (balance);
gst_gl_color_balance_update_properties (balance);
if (label) {
GstColorBalanceChannel *channel =
gst_gl_color_balance_find_channel (balance, label);
gst_color_balance_value_changed (GST_COLOR_BALANCE (balance), channel,
gst_color_balance_get_value (GST_COLOR_BALANCE (balance), channel));
}
}
static void
gst_gl_color_balance_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec)
{
GstGLColorBalance *balance = GST_GL_COLOR_BALANCE (object);
switch (prop_id) {
case PROP_CONTRAST:
g_value_set_double (value, balance->contrast);
break;
case PROP_BRIGHTNESS:
g_value_set_double (value, balance->brightness);
break;
case PROP_HUE:
g_value_set_double (value, balance->hue);
break;
case PROP_SATURATION:
g_value_set_double (value, balance->saturation);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}